Epoxy resins are known for their excellent chemical and thermal resistance, good electrical and mechanical properties and for their adhesion to a wide variety of substrates. Because of this, epoxy resins are presently used in many industrial applications.
When exposed to stress conditions, including heat and pressure, polymers derived from epoxy resins generally exhibit poor structural characteristics. Such polymers are generally brittle and when exposed to stress conditions, the polymer is highly susceptible to shrinking and cracking. To combat this problem, epoxy resins are generally utilized in combination with “fillers,” which can be made from a number of materials including particulate silica, ground quartz, alumina and aluminum hydride. This results in a more stable product that is less brittle and less susceptible to shrinkage and cracking. But with the addition of filler materials to the epoxy resins comes one drawback—what once may have been a transparent epoxy resin material may now be a non-transparent polymer with improved characteristics.
While non-transparent epoxy materials are useful in many instances, glass is still the major material used in the case where transparency is required. For example, bushings in utility and industrial transformers currently utilize a glass sight bowl to provide a three hundred and sixty degree view of the oil level in the bushing. Because of the extreme conditions in an operating bushing, including excessive heat and pressure, high strength glass is currently the only available material to provide the requisite electrical insulation and mechanical support while simultaneously providing a visible view of the oil level.
Thus, an epoxy material that can be produced with improved strength and stability characteristics, while remaining transparent, could have numerous practical industrial applications including, but not limited to, replacing presently-used glass sight bowls in utility and industrial high voltage bushings.